ASR 33 Emulation - help!

From: Derek Peschel <>
Date: Thu Oct 18 00:14:37 2001

On Wed, Oct 17, 2001 at 11:30:33PM -0400, wrote:
> Our sawmill uses an HP-1000 for process control; it has an infrared paper
> tape reader and an ASR 33 Teletype. And they all work. But I'd like to
> replace the teletype with a PC. Does anyone know how to make a PC emulate an
> ASR 33??
> Thanks

The last time I volunteered information, I got the connector size (of the
Mac floppy port) wrong. Oh well...

The ASR-33 uses ASCII over a serial line, so you don't have to deal with
strange character sets. (Older Teletypes use the 5-bit Murray code.)

However, you do have to deal with the speed (generally 110 baud -- can be
changed depending on gearing inside the ASR-33) and the circuit
configuration of the serial connection (it's a current loop; I couldn't tell
you what that means, but it's not RS-232 compatible). Your HP may expect
the eighth bit to be a parity bit, also.

There are adapters you can buy that convert between RS-232 and current loop.
I'm sure someone else on the list has them. (Allison? Chuck?)

If you want sound effects, yellow paper, faint blue printing, or the smell
of hot oily parts, you'll have to pay extra. :)

-- Derek
Received on Thu Oct 18 2001 - 00:14:37 BST

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